Dr. Paul Fedorchak of Plymouth State College is requesting a three year Academic Research Enhancement Award to perform a parametric series of experiments designed to describe the strength and character of conditioned flavor preferences. It is now well established that it is possible to condition preferences for arbitrary and neutral flavors by pairing them with caloric unconditioned stimuli. Furthermore, there is evidence that at least under some circumstances the flavor preference can be developed by pairing the CS with positive noncaloric taste stimuli such as saccharin. Still further, it may be possible (although problematic) to establish CFPs (i.e. conditioned flavor preferences) by using pharmacological unconditioned stimuli such as caffeine or morphine. As the PI summarizes his review of the literature, some of it being his own earlier work at the University of Washington, it would appear that there may be a gradient of reward potencies such that caloric Us > noncaloric taste Us > pharmacological Us. Complicating the interpretations of these phenomena, the findings supporting the efficacious of noncaloric taste and pharmacological stimuli are preliminary. They also are based on different experimental paradigms. To evaluate the apparent gradient of reward potencies, the PI proposes to approach the issue using a standardized within-experiment and within- laboratory set of comparisons. In all, the proposal involves three distinct aims. The first goal is to perform quantitative and rigorous estimate of the "gradient" using a factorial counterbalanced test paradigm for different Us from each category. The second goal is to determine whether conditioned flavor preferences established by the different types of Us (as well as particular individual stimuli within category) are affected by deprivation state. As the PI reviews, there is evidence that a CFP established by carbohydrate Us will increase with deprivation, but whether CFPs established by fats and other nutrients or nonnutrient tastes or pharmacological reinforcers will respond to hunger is not clear. The third goal is clarify the underlying nature of any of the CFPs obtained. Here the question of particular interest is to determine which of two processes is involved in the preference. On the one hand, CFPs may involve an absolute increase in preference in the target flavor such that preferences for unconditioned flavors, water or other tastes are not diminished. On the other hand, the CFPs (or some CFPs) may involve a relative increase in the target flavor achieved by decrease in the proportion of neutral flavors chosen in the taste situation. As the PI reviews, most of the testing on CFPs to date has used some variant of a two-bottle preference test which cannot discriminate between the two alternatives. A series of six factorial experiments designed to address these questions is proposed.